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101.
Nordin D Yarkoni O Donlon L Savinykh N Frankel D 《Chemical communications (Cambridge, England)》2012,48(5):672-674
Highly ordered ring-like structures are formed via the directed assembly of lipid domains in supported bilayers, using the extracellular matrix protein fibronectin. The ability of biological molecules to guide nanoscale assembly suggests potential biomimetic approaches to nanoscale structures. 相似文献
102.
Hanieh Kargarzadeh Ishak Ahmad Ibrahim Abdullah Alain Dufresne Siti Yasmine Zainudin Rasha M. Sheltami 《Cellulose (London, England)》2012,19(3):855-866
Cellulose nanocrystals (CNC) were first isolated from kenaf bast fibers and then characterized. The raw fibers were subjected
to alkali treatment and bleaching treatment and subsequent hydrolysis with sulfuric acid. The influence of the reaction time
on the morphology, crystallinity, and thermal stability of CNC was investigated. Fourier transform infrared spectroscopy showed
that lignin and hemicellulose were almost entirely removed during the alkali and bleaching treatments. The morphology and
dimensions of the fibers and acid-released CNC were characterized by field emission scanning electron microscopy and transmission
electron microscopy. X-Ray diffraction analysis revealed that the crystallinity first increases upon hydrolysis and then decreases
after long durations of hydrolysis. The optimal extraction time was found to be around 40 min during hydrolysis at 45 °C with
65% sulfuric acid. The thermal stability was found to decrease as the hydrolysis time increased. The electrophoretic mobility
of the CNC suspensions was measured using the zeta potential, and it ranged from −8.7 to −95.3 mV. 相似文献
103.
Numerical simulations utilizing computational fluid dynamics (CFD) with a volume of fluid (VOF) method has been employed to investigate two-phase flow distribution in inter-connected parallel flow channels. The interconnections resemble gas and liquid communications in fuel cell flow fields due to the inherent or artificial structures of gas diffusion layers (GDLs). The simulation results showed that communication between parallel channels could have a great impact on the two-phase flow pattern, gas and water distribution and flow maldistribution. Wide communication channels provide a pathway for gas to short-circuit the liquid, leading to a worsened gas flow distribution. However, when the communication channels are narrow enough, they are helpful for mitigating the flow maldistribution by redistributing the liquid among the parallel flow channels through the communication channels. The simulation results were also verified by comparing the predicted and measured normalized pressure drop and the gas flow ratios at the entrance section of experimental parallel channels. 相似文献
104.
A. Mahdy 《ournal of non Newtonian Fluid Mechanics》2010,165(11-12):568-575
A non-similar boundary layer analysis is presented to study the flow, heat and mass transfer characteristics of non-Darcian mixed convection of a non-Newtonian fluid from a vertical isothermal plate embedded in a homogeneous porous medium with the effect of Soret and Dufour and in the presence of either surface injection or suction. The value of the mixed-convection parameter lies between 0 and 1. In addition, the power-law model is used for non-Newtonian fluids with exponent n < 1 for pseudoplastics n = 1 for Newtonian fluids and n > 1 for dilatant fluids. Furthermore, the coordinates and dependent variables are transformed to yield computationally efficient numerical solutions that are valid over the entire range of mixed convection, from the pure forced-convection limit to the pure free-convection limit, and the whole domain of non-Newtonian fluids, from pseudoplastics to dilatant fluids. The numerical solution of the problem is derived using a Runge–Kutta integration scheme with Newton–Raphson shooting technique. Distributions for velocity, temperature and concentration, as well as for the rate of wall heat and mass transfer, have been obtained and discussed for various physical parametric values. 相似文献
105.
Hao Shao Xuebin Zhang Fanyan Chen Shasha Liu Yi Ji Yajun Zhu Yi Feng 《Applied Physics A: Materials Science & Processing》2012,109(4):961-965
In this paper, smooth α-Fe2O3 nanotubes have been successfully synthesized by electrospinning of ferric nitrate–polyvinyl alcohol solution followed by calcination in air. The morphologies and structures of the samples were characterized by transmission electron microscopy, scanning electron microscopy and X-ray diffraction. The catalytic properties were studied by differential thermal analysis and thermogravimetric analysis. The results indicated that the as-prepared α-Fe2O3 nanotubes showed a continuous morphology and an extremely high degree of crystallization. The average inner and outer diameters of the obtained α-Fe2O3 nanotubes were about 60 nm and 100 nm, respectively. The obtained α-Fe2O3 nanotubes were able to lower the temperature of the high-temperature thermal decomposition of ammonium perchlorate, while they had little effect on the crystallographic phase transformation and the low-temperature thermal decomposition. 相似文献
106.
Azizi Masitah Abdul Halim Isahak Wan Nor Roslam Wan Masdar Mohd Shahbudin Somalu Mahendra Rao Yarmo Mohd Ambar 《Research on Chemical Intermediates》2018,44(11):6787-6802
Research on Chemical Intermediates - Hydrogen is considered a promising energy carrier for the future, especially for clean energy generation via fuel cell technologies. Formic acid is one of the... 相似文献
107.
In this Letter, approximate solutions of singular two-point boundary value problems (BVPs) are obtained by the modified homotopy analysis methods (MHAM). MHAM provides a convenient way of controlling the convergence region and rate of the series solution. The numerical tests show the capability of MHAM for singular BVPs. 相似文献
108.
N. N. Binitha P. V. Suraja Z. Yaakob M. R. Resmi P. P. Silija 《Journal of Sol-Gel Science and Technology》2010,53(2):466-469
In this work we describe and discuss the synthesis, and characterization of Co3O4 nanoflakes prepared by citric acid based sol–gel method using cobalt nitrate precursor. The average crystalline size of Co3O4 was estimated from the X-ray diffraction peaks of powders using Scherrer’s formula. The size of the particles deduced from
TEM agrees with XRD based values. The FTIR confirms formation of Co3O4. The SEM micrographs show the nanoflake morphology. Here we report the lowest temperature sol–gel method of preparation of
Co3O4 nanoflakes and its photocatalytic study for the degradation of dye pollutant methylorange. 相似文献
109.
R. N. Jat Santosh Chaudhary 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2010,45(6):1151-1154
The radiation effects using the Rosseland approximation on the flow of an incompressible viscous electrically conducting fluid
over a stretching sheet near the stagnation point in the presence of uniform transverse magnetic field is studied. The governing
equations transform to ordinary differential equation by using suitable similarity transformation and then by a perturbation
technique the numerical results for temperature distribution were obtained and discussed graphically. 相似文献
110.
Similarity solutions for mixed convection boundary layer flow over a permeable horizontal flat plate
The effects of suction and injection on steady laminar mixed convection boundary layer flow over a permeable horizontal flat plate in a viscous and incompressible fluid is investigated in this paper. The similarity solutions of the governing boundary layer equations are obtained for some values of the suction and injection parameter f0, the constant exponent n of the wall temperature as well as the mixed convection parameter λ. The resulting system of nonlinear ordinary differential equations is solved numerically for both assisting and opposing flow regimes using a finite-difference scheme known as the Keller-box method. Numerical results for the reduced skin friction coefficient, the reduced local Nusselt number, and the velocity and temperature profiles are obtained for various values of the parameters considered. Dual solutions are found to exist for the opposing flow. 相似文献